The goal of this proposal is to discover the neural underpinnings of the normal development of declarative memory (conscious memory for events and facts). Declarative memory is critical for everyday life and essential for education, but virtually nothing is known about the normal functional development of the neural circuits underlying either the encoding or the retrieval of declarative memories. We propose to use functional magnetic resonance imaging (fMRI) to examine the development of declarative memory systems in the maturing human brain. Preliminary Studies motivate the initial hypothesis that medial temporal lobe mnemonic functions mature prior to prefrontal cortical mnemonic functions. We propose 9 cross sectional and 2 longitudinal experiments to elucidate the normal development of declarative memory. In each experiment, we compare 20 children ages 8-12, 20 adolescents ages 13-17 and 26 adults ages 18-30 (stratified by age and sex). All participants will be characterized with behavioral measures in terms of cognitive and memory abilities. The first stage of memory involves the encoding of current experiences into long-term memory. In Experiments 1-6, we examine the neural substrates of (1) verbal memory encoding for item and source;(2) visuospatial memory encoding (3) self-instructed intentional vs. experimenter-instructed incidental memory encoding;(3) controlled versus automatic encoding;(4) the intention to encode vs. the success of encoding;(5) the relation between maintaining information in working memory and memory encoding;and (6) control of attention and memory encoding. The final stage of memory performance involves the retrieval of information from long-term memory in service of a current goal. Experiments 7-9 examine the retrieval of declarative memory. We examine the neural substrates of (1) retrieval of visuospatial memories;(2) retrieval of source information when source is well remembered;and (3) retrieval for source information when source is less well remembered. In each experiment, we relate behavioral measures to fMRI measures, and compare between children adolescents and adults. In addition, we propose to re-test two group of subjects after three years to examine the longitudinal development of declarative memory encoding and retrieval. According to the American Academy of Child and Adolescent Psychiatry, one in ten children suffer from a learning disorder. It is impossible to begin to understand the brain bases of learning disorders without a reasonable understanding of how learning develops in the typical, healthy brain. We hope these studies will provide a useful step forward in developing a cognitive neuroscience framework of normal memory development that can be used to begin to understand the brain basis of learning disorders.